To enable hearing aids to offer the optimum benefits to their wearers they must compensate for the hearing problem. A hearing aid primarily compensates for a hearing impairment by amplifying the incoming signals sufficiently. Modern hearing aids can be adapted to a wearer's individual needs. In practice such adaptation presents difficulties, so that the hearing aid wearer is not always catered for in the best possible manner.
With modern hearing aids a plurality of adaptable parameters can be adapted to the wearer, e.g. the sound pressure level as a function of the frequency, type and degree of noise reduction, the control time, and much more besides. Previously adaptation has involved measuring the different hearing thresholds (depending on the frequency) of the wearer. Based on these measurements, specific adaptation formulas can be used for suitable adaptation and the necessary amplification for the hearing aid can be determined. Examples of such adaptation formulas are the DSL (Desired Sensation Level) method described in Bagatto et al., (2005), Clinical protocols for hearing instrument fitting in the DSL method, trends amplification, 9(4):199-226, or the NAL-NL1 method (National Acoustics laboratories “non-linear fitting Version 1”). One problem with these adaptation methods lies in the fact that they require measurements to be taken on or in the ear of the wearer and the latter's cooperation is required. The methods are frequently lengthy and, with small children especially, are difficult or even impossible to perform.
It is known that many hearing problems have genetic causes, see also Schrijver, Hereditary non-syndromic sensorineural hearing loss, transforming silence to sound, (2004), Journal of Molecular Diagnostics, 6(4), 275-284. Hearing problems with genetic origins are widespread. Appr. 1 in 1000 children is born deaf and 1 in 300 children has a congenital loss of hearing, a further 1 in 1000 children suffers a significant loss of hearing before reaching adulthood. There is a genetic cause in around 50% of these cases. Hearing problems with genetic origins occur for different reasons, it is estimated that around 1% of all human genes play a part in the hearing process. In 70% of all cases a hearing loss with genetic origins is non-syndromic, i.e. hearing loss with genetic origins is not connected with an easy-to-diagnose syndrome, such as Usher Syndrome and similar syndromes for example. Hearing loss with genetic origins can be inherited in an autosomal recessive (AR), autosomal dominant (AD), x-chromosomal (X) or mitochondrial (mito) manner.